1. Field
This disclosure generally relates to the fabrication of fiber reinforced resin laminates, and deals more particularly with a method of exposing the reinforcing fibers in a laminate. The disclosure also relates to a method of bonding fiber reinforced resin laminates.
2. Background
Several techniques are commonly used to join the faying surfaces of composite parts, such as fiber reinforced resin laminates. For example, faying surfaces of laminate parts may be joined together by compressing and co-curing them together. A relatively strong joint may be achieved by co-curing the laminates because the resin matrix along the faying surfaces of the parts flow together, consolidate and may cross-link during the curing process. Alternatively, faying surfaces of two pre-cured laminate parts may be joined together with a bonded joint using a bonding adhesive that is cured while the parts are compressed together, otherwise known as co-bonding and secondary bonding.
Under ideal conditions these bonded joints may be as strong and robust as those that result from co-curing the laminate parts. However, surface preparation must be near perfect and the margin for error when bonding the parts is quite small because the bonded area, commonly referred to as a bondline, is relatively thin and does not substantially encompass the reinforcing fibers of the laminate parts. Cracks may propagate along surfaces of bondlines that are not adequately prepared before bonding. Because of these problems, bonded joints are often reinforced with mechanical fasteners to provide an added measure of reliability. The use of mechanical fasteners is undesirable, however, because they add weight to the structure, require additional material and labor, and may necessitate the use of higher volumes of reinforcing fibers in order to compensate for possible weakening of the structure due to the presence of fastener holes.
Accordingly, there is a need for a method of joining fiber reinforced laminate parts using a bonded joint that provides the strength and reliability needed to reduce or eliminate the need for mechanical fasteners.